This invention pertains to the art of entrance fittings and more particularly to wire entrance fittings.
The invention is particularly applicable to a water tank corrosion protection system and will be described with particular reference thereto. However, it will be appreciated that the invention has broader applications and may be advantageously employed in other environments and applications.
Typically, prior art wire entrance fittings for use in cathodic protection systems for water tanks or the like have suffered as a result of water migrating to the outside of the tank. These fittings generally utilized a straight tubular member having a flange attached along an exterior portion thereof. The fitting was positioned so that the flange was normally disposed adjacent an interior surface of the tank side wall. In this position, the flange compressingly held a seal ring, such as an elastomeric O-ring, in sealing engagement with the tank wall interior. Plural apertures were formed in the pipe member to receive the necessary wires for the cathodic protection system therethrough. The wires themselves then completely extended through the tank side wall for connection to a junction box or the like.
Even though the wires themselves included an insulation layer, water migration was still perceived on the tank exterior. It is believed that the water migrated to the tank exterior between the insulation layer and the wire itself.
Yet another problem resulted from the formation of ice in the water tank interacting with the wire assembly of the cathodic protection system. Formation of ice in the water tank can have an adverse effect on the anode assembly of a cathodic protection device. In other prior art systems, increased tensile forces were imposed on the wire assembly extending between the anodes suspended in the water tank and the wire entrance fitting communicating through the tank side wall with an external power supply. Pullout forces were exerted on the wires at the entrance fitting. These pullout forces were sufficiently large to completely disengage the wires from the remainder of the entrance fitting. Dislodgement of the wires thereby left plural apertures completely through the entrance fitting. Subsequent water leakage through these apertures was, of course, a problem.
It has, therefore, been considered desirable to provide a new entrance fitting that eliminates water migration through the tankwall when a cathodic protection system is employed. Additionally, the new entrance fitting should be able to withstand pullout forces generated as a result of ice formation and the like. The subject invention provides a new and improved wire entrance fitting that overcomes all of the above referred to problems and others and that facilitates installation in a water tank.